1. Field of the Invention
This invention relates to a novel method and apparatus for the control of animals without ground-based fencing.
2. Description of the Prior Art
Livestock, particularly ruminants such as cattle, as well as other animals including pigs, horses, burros and other monogastrics, are currently controlled within defined inclusion zones (pastures) by ground-based fencing. Fences may be constructed of various building materials including metal alloys, wood and stone. Wire is the most common modern conventional fencing material for controlling animals on large areas. Wire fencing can take various forms including individual smooth and barbed wires or a combination of individual wires woven into fabrics of various design and heights. Wire fencing requires attachment to a ground-based support, most commonly a wood, metal, concrete, plastic or synthetic polymer post. Insulators may be required between the wire and the post if electrical charge is to be carried in the wires.
The need for wire material and its subsequent support make wire fence expensive on a per lineal distance basis. Add to the cost of materials the labor required to install the fence and additional labor required to maintain these structures and substantial economic costs are incurred using this method of animal control. In addition, ground-based fences have critical disadvantages above those associated with direct costs. Most ground-based fencing systems are not easily moved on a frequent basis and as such their static position on the landscape thwarts flexible management, especially those strategies focused on promoting proper utilization of the vegetation resource. Neither the vegetation resource nor the herbivory among ecosystems is static in time or space. Therefore, it logically follows that control of foraging animals on these ecosystems should likewise not be static. Fragile ecosystems, such as riparian areas, are not served well by conventional fencing systems that inhibit flexible management. These ecosystems require the flexible spatial and temporal control of animals which conventional fencing systems cannot provide on a cost affective basis. Furthermore, conventional wire fencing is considered by many to have undesirable aesthetic implications in addition to disrupting the movement of many wildlife species.
In the recent past electronic-based containment systems have been described for several animal species, particularly pets and specifically canines. However, electronic devices for controlling livestock have also been described (Quigley, U.S. Pat. No. 5,408,956). All previously described electronic systems for controlling animal location require ground-based equipment in addition to devices attached to an animal. The ground-based transmitters are located at remote and fixed locations but always within range of the most-distant transponder in the system (Janning, U.S. Pat. No. 5,241,923). The transmitter emits a signal which is picked up by a receiver worn by the animal. Most systems relay on Radio Frequency (RF) signals generated from ground-based transmitters; however, some systems utilize near infrared (McCarney et al., U.S. Pat. No. 5,608,381) or compressional wave beams (Bianco, U.S. Pat. No. 5,640,932). Frequently the receiver is attached to a collar (Gonda, U.S. Pat. No. 5,099,797) that is worn around the animal's neck. The aversive stimuli are either under manual or automatic ground-based control. Before the invention described herein, only voice commands (Yarnall, Sr. et al., U.S. Pat. No. 4,745,882) and human activation of the aversive stimuli were employed in an attempt to return an animal to the area from which it had escaped.
Some devices have been developed to keep individual animals apart over short ranges (Davis et al., U.S. Pat. No. 5,575,242 and Van Curen et al., U.S. Pat. No. 5,636,597). Aversive stimuli in prior art are administered to the animal solely at the discretion of an observer and not bilaterally. Depending on the skill of the human handler in interpreting and initiating stimulation, desirable changes in the behavior of the animal vary. The sequence of stimuli used to alter behavior in prior art occur in various combinations to condition the animal to give a reasonably predictable response to enhance the animal's safety and/or usefulness to the owner.
All previous ground based electronic containment systems depended on line-of-sight to transmit signals to the animal wearing the receiver. Hence undulating topography has limited the usefulness of prior art to relatively small zones of inclusion in which animals could be monitored and controlled. Only recently have RF signals emanating from satellites been incorporated into animal control devices but only to provide accurate information on animal location. The current uses of the Global Positioning System (GPS), especially in biology, appear to be focused on determining the location of animals or in Precision Agriculture on the agronomic application or removal of materials from fields. Using GPS as a technology to train animals has only been referenced by Files (Files, U.S. Pat. No. 5,857,433). Until recently GPS and more specifically Differential (DGPS) has been investigated as a tool for steering inanimate objects (Herring, 1996, Scientific American, 274(2):44-50).
In general, prior art operates through a field transmitter (e.g., Janning, U.S. Pat. No. 5,241,923) that emits a continuous, coded signal of designated strength. This electronic signal defines a zone, from which animals are to be excluded. Where systems have been described to operate remotely frequently there are wires laying on or just below the surface of the ground to serve as ground-based transmitters or emitters to make contiguous loops (Touchton et al., U.S. Pat. No. 5,435,271). If above ground transmitters are used 1/8 to 1/2 mile separation has been reported between transmitters and receivers (Gonda, U.S. Pat. No. 5,193,484). Signals emanating from a central point (Brose, U.S. Pat. No. 4,898,120) or a lobe of radiation enclosing animals can be rotated around a fixed point in a 360.degree. circle (Aine, U.S. Pat. No. 5,121,711) to facilitate rotational grazing. However, the relatively short distances over which electronic signals can be beamed with ground based systems makes prior art of minimal usefulness for animal control over vast areas and variable topography.
Power requirements continue to present a challenge to electronic animal control systems. Grimsley et al. (U. S. Pat. No. 5,682,839) has incorporated motion sensors to power down systems when the animals are not in motion as a means to conserve battery power.
Psychological and ethological literature abounds on the use of instructional conditioning to train animals to avoid aversive stimuli. Apparatuses using conditioning to administer aversive stimuli to domestic pets have been patented under the title of training and restraining systems including Westrick et al., U.S. Pat. No. 5,559,498.
Sound and electric shock transducers apply the predominant forms of motivational stimuli. Acoustic audio stimuli include beeps (Custer, U.S. Pat. No. 5,465,687), whistles (Fury, U.S. Pat. No. 3,980,051) or a combination of sounds (Gonda et al., U.S. Pat. No. 4,335,682) including the human voice (Yarnall, Jr. et al., U.S. Pat. No. 5,565,850; Kim et al., U.S. Pat. No. 5,605,116) used in conjunction with electrical shock in various patterned combinations (Gonda et al., U.S. Pat. No. 4,802,482), sequences and durations.
Electric shock is normally administered from a single pair of electrodes. An attempt has been described for reducing the occurrence of spurious signals that could induce aversive stimuli to an animal when it was not requested by the handler (Touchton et al., U.S. Pat. No. 5,576,694). McDade et al. (U.S. Pat. No. 5,207,178) describes a shock collar that contains one fixed pair of electrodes and two individual electrodes that can be moved to different positions on the collar.
Current art appears to utilize acoustic stimuli in combination with electric shock without regard to applying it to a specific location and side of the animal in order to change the animal's direction of movement. Furthermore, motivational stimuli in current art are not easily changed once established (Touchton et al., U.S. Pat. No. 5,435,271) and at best appear limited to only a few preset levels (Gonda et al., U.S. Pat. No. 4,802,482). For example, in one device the level of electric shock stimulation could only be varied by interchanging electrode structures having various resistances (Gonda et al., U. S. Pat. No. 5,471,954). This limitation in prior art makes it difficult if not impossible to change stimuli patterns in real-time based upon immediate management needs and conditions.